131 lines
6.4 KiB
Markdown
131 lines
6.4 KiB
Markdown
---
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description: "Telegraf plugin for collecting metrics from Kernel"
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menu:
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telegraf_v1_ref:
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parent: input_plugins_reference
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name: Kernel
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identifier: input-kernel
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tags: [Kernel, "input-plugins", "configuration", "system"]
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introduced: "v0.11.0"
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os_support: "linux"
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related:
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- /telegraf/v1/configure_plugins/
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- https://github.com/influxdata/telegraf/tree/v1.36.1/plugins/inputs/kernel/README.md, Kernel Plugin Source
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---
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# Kernel Input Plugin
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This plugin gathers metrics about the [Linux kernel](https://kernel.org/) including, among
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others, the [available entropy](https://www.kernel.org/doc/html/latest/admin-guide/sysctl/kernel.html#random), [Kernel Samepage Merging](https://www.kernel.org/doc/html/latest/mm/ksm.html) and
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[Pressure Stall Information](https://www.kernel.org/doc/html/latest/accounting/psi.html).
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**Introduced in:** Telegraf v0.11.0
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**Tags:** system
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**OS support:** linux
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[kernel]: https://kernel.org/
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[entropy]: https://www.kernel.org/doc/html/latest/admin-guide/sysctl/kernel.html#random
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[ksm]: https://www.kernel.org/doc/html/latest/mm/ksm.html
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[psi]: https://www.kernel.org/doc/html/latest/accounting/psi.html
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## Global configuration options <!-- @/docs/includes/plugin_config.md -->
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In addition to the plugin-specific configuration settings, plugins support
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additional global and plugin configuration settings. These settings are used to
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modify metrics, tags, and field or create aliases and configure ordering, etc.
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See the [CONFIGURATION.md](/telegraf/v1/configuration/#plugins) for more details.
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[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins
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## Configuration
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```toml @sample.conf
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# Plugin to collect various Linux kernel statistics.
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# This plugin ONLY supports Linux
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[[inputs.kernel]]
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## Additional gather options
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## Possible options include:
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## * ksm - kernel same-page merging
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## * psi - pressure stall information
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# collect = []
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```
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Please check the documentation of the underlying kernel interfaces in the
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`/proc/stat` section of the [proc man page](http://man7.org/linux/man-pages/man5/proc.5.html), as well as in the
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`/proc interfaces` section of the [random man page](https://man7.org/linux/man-pages/man4/random.4.html).
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Kernel Samepage Merging is generally documented in the
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[kernel documentation](https://www.kernel.org/doc/html/latest/accounting/psi.html) and the available metrics exposed via sysfs
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are documented in the [admin guide](https://www.kernel.org/doc/html/latest/admin-guide/mm/ksm.html#ksm-daemon-sysfs-interface).
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Pressure Stall Information is exposed through `/proc/pressure` and is documented
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in [kernel documentation](https://www.kernel.org/doc/html/latest/accounting/psi.html). Kernel version 4.20+ is required.
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[ksm_admin]: https://www.kernel.org/doc/html/latest/admin-guide/mm/ksm.html#ksm-daemon-sysfs-interface
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[man_proc]: http://man7.org/linux/man-pages/man5/proc.5.html
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[man_random]: https://man7.org/linux/man-pages/man4/random.4.html
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## Metrics
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- kernel
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- boot_time (integer, seconds since epoch, `btime`)
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- context_switches (integer, `ctxt`)
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- disk_pages_in (integer, `page (0)`)
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- disk_pages_out (integer, `page (1)`)
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- interrupts (integer, `intr`)
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- processes_forked (integer, `processes`)
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- entropy_avail (integer, `entropy_available`)
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- ksm_full_scans (integer, how many times all mergeable areas have been scanned, `full_scans`)
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- ksm_max_page_sharing (integer, maximum sharing allowed for each KSM page, `max_page_sharing`)
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- ksm_merge_across_nodes (integer, whether pages should be merged across NUMA nodes, `merge_across_nodes`)
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- ksm_pages_shared (integer, how many shared pages are being used, `pages_shared`)
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- ksm_pages_sharing (integer,how many more sites are sharing them , `pages_sharing`)
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- ksm_pages_to_scan (integer, how many pages to scan before ksmd goes to sleep, `pages_to_scan`)
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- ksm_pages_unshared (integer, how many pages unique but repeatedly checked for merging, `pages_unshared`)
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- ksm_pages_volatile (integer, how many pages changing too fast to be placed in a tree, `pages_volatile`)
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- ksm_run (integer, whether ksm is running or not, `run`)
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- ksm_sleep_millisecs (integer, how many milliseconds ksmd should sleep between scans, `sleep_millisecs`)
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- ksm_stable_node_chains (integer, the number of KSM pages that hit the max_page_sharing limit, `stable_node_chains`)
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- ksm_stable_node_chains_prune_millisecs (integer, how frequently KSM checks the metadata of the pages that hit the deduplication limit, `stable_node_chains_prune_millisecs`)
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- ksm_stable_node_dups (integer, number of duplicated KSM pages, `stable_node_dups`)
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- ksm_use_zero_pages (integer, whether empty pages should be treated specially, `use_zero_pages`)
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- pressure (if `psi` is included in `collect`)
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- tags:
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- resource: cpu, memory, or io
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- type: some or full
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- floating-point fields: avg10, avg60, avg300
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- integer fields: total
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## Example Output
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Default config:
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```text
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kernel boot_time=1690487872i,context_switches=321398652i,entropy_avail=256i,interrupts=141868628i,processes_forked=946492i 1691339564000000000
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```
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If `ksm` is included in `collect`:
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```text
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kernel boot_time=1690487872i,context_switches=321252729i,entropy_avail=256i,interrupts=141783427i,ksm_full_scans=0i,ksm_max_page_sharing=256i,ksm_merge_across_nodes=1i,ksm_pages_shared=0i,ksm_pages_sharing=0i,ksm_pages_to_scan=100i,ksm_pages_unshared=0i,ksm_pages_volatile=0i,ksm_run=0i,ksm_sleep_millisecs=20i,ksm_stable_node_chains=0i,ksm_stable_node_chains_prune_millisecs=2000i,ksm_stable_node_dups=0i,ksm_use_zero_pages=0i,processes_forked=946467i 1691339522000000000
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```
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If `psi` is included in `collect`:
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```text
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pressure,resource=cpu,type=some avg10=1.53,avg60=1.87,avg300=1.73 1700000000000000000
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pressure,resource=memory,type=some avg10=0.00,avg60=0.00,avg300=0.00 1700000000000000000
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pressure,resource=memory,type=full avg10=0.00,avg60=0.00,avg300=0.00 1700000000000000000
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pressure,resource=io,type=some avg10=0.0,avg60=0.0,avg300=0.0 1700000000000000000
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pressure,resource=io,type=full avg10=0.0,avg60=0.0,avg300=0.0 1700000000000000000
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pressure,resource=cpu,type=some total=1088168194i 1700000000000000000
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pressure,resource=memory,type=some total=3463792i 1700000000000000000
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pressure,resource=memory,type=full total=1429641i 1700000000000000000
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pressure,resource=io,type=some total=68568296i 1700000000000000000
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pressure,resource=io,type=full total=54982338i 1700000000000000000
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```
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Note that the combination for `resource=cpu,type=full` is omitted because it is
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always zero.
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